Container with integral tear strip



Jan. 23, 1968 a. B. LIPSKE CONTAINER WITH INTEGRAL TEAR' STRIP 2 Sheets-Sheet 1 Filed June 26, 1964 INVENTOR B NJAMIN B. L PSKE Jan. 23, 1968 I B. B. LIPSKE 3,355,095,.

CONTAINER WITH INTEGRAL TEAR STRIP Filed June 26, 1964 2 Sheets-Sheet 2 INVENI'bR Bemmwnm B. LIPSKE ATTY.

3,365,095 CONTAINER WITH INTEGRAL TEAR STRIP assignor to 11]., a corpora- This invention relates in general to containers of the so-called tin can type, and more particularly to cans having tear strip opening devices.

It is known in the art to provide a can end with one or more pre-scored lines around the periphery thereof to constitute a line or strip of tear for removal of a portion of the can end. Usually there is a tear strip defining the initial portion of the tear line or strip, this initial portion often extending inwardly from the peripheral tear line and having a tab secured thereto and by which the tearing is initiated. These tabs have been secured to the initial portion of the score line in various ways, as by Welding, soldering, or riveting; however, all of these ways have certain drawbacks to the high speed production of reliable containers.

It is an object of the present invention to provide a can having a can end of the general type stated in which the need for riveting, soldering, or welding the tear tab to the tear strip is eliminated. This is accomplished by forming a slit in the can end at the terminal of the tear strip to define the tab, the slit being sealed by tapes over the tab on the inside and outsde of the can end and with the outside tape being removable from the can end to bend the adhered thereto tab upwardly from the plane of the can end and also tear the inside tape. Thereafter, the tab may be grasped to tear the reminder of the strip and the peripheral score line or lines of the can end to remove a part of the can end from the can.

It is a further object of the present invention to provide a can of the type stated in which the tapes are bonded to the can end by a suitable adhesive, such as a thermoplastic adhesive. The tapes may be of thermoplastic resin, as for instance polyester resin, which will bond to the can end, or the tapes may be of metal foil which has been pre-coated with the thermoplastic resin adhesive so that the tapes may be placed in position and then by heat and pressure bonded in place to form an hermetic seal across the slits. In some instances the tape on the inside of the can end may be eliminated, as for instance where there would be no product reaction by reason of product contact with the raw edges of metal at the slit.

It is another object of the present invention to provide a can of the type stated which is suitable for use with products requiring an enamel lined can since the bonding of the tape to the can end does not cause a break in the enamel coating thereon.

The attainment of the above and further objects of the present invention will be apparent from the following specification taken in conjunction with the accompanying drawing forming a part thereof.

In the drawing:

FIG. 1 is a top plan view of a can end constructed in accordance with and embodying the present invention;

FIGS. 2, 3 and 4 are sectional views taken along lines 22, 3-3 and 4 4 respectively of FIG. 1;

FIG. 5 is a sectional view through the central axis of a can having as a part thereof the can end of FIG.1;

FIG. 6 is a fragmentary perspective view showing the manner of opening the can of the present invention;

FIG. 7 is a top plan view of a modified form of can end constructed in accordance with the present invention; and

FIG. 8 is a sectional view taken along line 88 of FIG. 7.

3,365,995 Patented Jan. 23, 1968 Referring now in more detail to the drawing, which illustrates a preferred embodiment of the present invention, 1 designates a can end that is fabricated of sheet metal, for instance of tinplate or aluminum. The can end 1 includes a circular disc 3 which is surrounded by a generally conical wall 4, the radially outer end of which has an annular peripheral flange 6 by which the can end may be seam sealed to a can body in the usual manner.

At the periphery of the disc 3 there is a score line 7 that extends 360 degrees, or nearly so, around the disc. Extending generally inwardly from the score line 7 is a line of Weakness 9 that defines a tear initiating strip 11. The line of weakness 9 includes a generally arcuate score line 13 that extends generally radially inwardly from the score line 7, and a generally arcuate score line 15 that extends from a point 17 spaced radially inwardly of the score line 7, the two score lines 13, 15 terminating in spaced apart points 19, 21. The remainder of the line of weakness 9 is a U-shaped slit or cut 23 through the disc 3, running between the points 19, 21, with the bight 25 of the U extending partially around the center of the disc 3 whereby the slit 23 defines radially extending tear initiating tab 27 at the end of the strip 11. For purposes of clarity of illustration, the slit 23 is shown of exaggerated size in the drawing as a double dotted line.

Bonded to the inside surface 29 of the disc 3 is a tape 31 which is preferably oil and water proof. This tape 31 may be of a known type, for instance polyester resin tape. Such tape is thermoplastic and may be bonded by heat and pressure to the surface 29. A tape 33 is also bonded to the outside surface 35 of the disc 3. The tape 33 is preferably of metal foil, such as aluminum or tinplate, which has been pre-coated on one side with a layer adhesive 36. The adhesive 36 may 'be of any suitable type, including a polyester resin, so that the foil tape 33 may be bonded by heat and pressure to the disc 3 at the same time that the tape '31 is bonded to the surface 29. Each of the tapes 31, 33 are bonded to their respective surfaces 29, 35 of the disc 3 over areas that cover the tear initiating tab 27 and portions of the disc 3 adjacent thereto so as to form an hermetic seal over the slit 23. However, a small strip 38 of the foil tape 33 is left unbonded to the surface 35 adjacent to the bight 25, for purposes presently more fully appearing. While the tape 31 is preferably plastic, it may be of plastic coated foil like the tape 33. In some instances, as where contact of the product with the can with the raw edge of metal at the slit is unobjectionable, the tape 33 may be omitted.

Can ends of the type described may be fabricated as a unit and thereafter attached to a can body 39 that has a cylindrical body Wall 40 formed of a sheet of metal, such as tinplate, aluminum, or backplate, shaped into tubular form with mating edges of the sheet overlapped and secured to form a longitudinal side seam 41. The peripheral flange 6 is secured to the adjacent material at one end of the body wall 40 to form an end seam 42. A conventional can end 4 may be secured by an end seam 46 to the other end of the body wall 40.

When it is desired to open the can, the free portion 38 of the tape 33 is grasped to tear the tape 33 from the surface 35 of the disc 3. The tab 27 remains adhered to the tape 33 so that the tab 27 bends upwardly out of the plane of the disc 3. At the same time the inner tape 31 is torn along the slit 23, the torn portion 48 of the tape 3-1 remaining adhered to the tab 27. With the tab 27 now projecting upwardly from the disc 3, the tab 27 may be grasped, as shown in FIG. 6, to tear the remainder of the strip 11 along the score lines 13, 15 and then tear the disc 3 along the peripheral score line 7 so that the disc 3 may be removed from the can. The tapes 31, 33 remain secured to the removed portion of the disc so that the entire removed portion may be discarded as a unit.

FIGURES 7 and 8 show a modified form of can end In which is similar to the can end 1, previously described. However, in the can end 1a the tear strip 11 lies between the center of the disc and the score line 7. Moreover, the sides 51 of th tapes 31, 33 taper so that the free portion 33a is narrower than the remainder of the tape 33.

In compliance with the requirements of the patent statutes 1 have herein shown and described a preferred embodiment of the invention. It is, however, to be understood that the invention is not limited to the precise con struction herein shown, the same being merely illustrative of the principles of the invention.

What is considered new and sought to be secured by Letters Patent is:

1. A can end comprising a disc with peripheral means surrounding the disc for attachment to a can body, a first score line extending around said disc adjacent to and inwardly of said peripheral means and constituting a path for fracturing the disc to remove a part thereof, a second generally arcuate score line extending generally radially inwardly from the first score line, a third score line extending over only a minor fractional part of the circumferential extent of said disc and running from a first point radially inwardly of the first score line along an arcuate path that runs radially outwardly of said one point and then radially inwardly of said one point to a second point that forms the terminal of said third score line that is spaced from the terminus of said second score line, a generally U-shaped line of slit through said disc that extends from the terminus of said second score line to said second point and defining a tear-initiating tab, and means bonded to the disc over the tab and over the slit to form a seal thereacross, said means including a gas impervious tape on the outside surface of said disc and having a part thereof that is free from said disc and which may be grasped to rupture said means at the slit and bend the tab out of the place of said disc to enable the tab to be grasped to tear the disc initiailly along the second and third score lines and then tear the disc along the first score line.

2. A can end according to claim 1 in which said means further comprises a plastic on the inside surface of the disc and covering the slit.

References Cited UNITED STATES PATENTS 2,147,004 2/1939 Wark et a1. 220-47 2,870,935 8/1959 Houghtelling 220-53 3,144,194 8/1964 Cartwright 22951 3,182,852 5/1965 Wilkinson 22054 3,187,931 6/1965 Henchert 22054 3,250,426 5/ 1966 Fraze 22054 3,251,515 5/1966 Henchert et al. 22053 THERON E. CONDON, Primary Examiner.

LOUIS G. MANCENE, G. T. HALL, Examiners. 

1. A CAN END COMPRISING A DISC WITH PERIPHERAL MEANS SURROUNDING THE DISC FOR ATTACHMENT TO A CAN BODY, A FIRST SCORE LINE EXTENDING AROUND SAID DIAC ADJACENT TO AND INWARDLY OF SAID PERIPHERAL MEANS AND CONSTITUTING A PATH FOR FRACTURING THE DISC TO REMOVE A PART THEREOF, A SECOND GENERALLY ARCUATE SCORE LINE EXTENDING GENERALLY RADIALLY INWARDLY FROM THE FIRST SCORE LINE, A THIRD SCORE LINE EXTENDING OVER ONLY A MINOR FRACTIONAL PART OF THE CIRCUMFERENTIAL EXTENT OF SAID DISC AND RUNNING FROM A FIRST POINT RADIALLY INWARDLY OF THE FIRST SCORE LINE ALONG AN ARCUATE PATH THAT RUNS RADIALLY OUTWARDLY OF SAID ONE POINT AND THEN RADIALLY INWARDLY OF SAID ONE POINT TO A SECOND POINT THAT FORMS THE TERMINAL OF SAID THIRD SCORE LINE THAT IS SPACED FROM THE TERMINUS OF SAID SECOND SCORE LINE, A GENERALLY U-SHAPED LINE OF SLIT THROUGH SAID DISC THAT EXTENDS FROM THE TERMINUS OF SAID SECOND SCORE LINES TO SAID SECOND POINT AND DEFINING A TEAR-INITIATING TAB, AND MEANS BONDED TO THE DISC OVER THE TAB AND OVER THE SLIT TO FORM A SEAL THEREACROSS, SAID MEANS INCLUDING A GAS IMPERVIOUS TAPE ON THE OUTSIDE SURFACE OF SAID DISC AND HAVING A PART THERE- 